package org.budo.icbc.sdk.util;

//重写这个类，解决换行问题
public class BASE64Encoder {
	  private static char[] codec_table = { 'A', 'B', 'C', 'D', 'E', 'F', 'G',
          'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
          'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
          'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
          'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6',
          '7', '8', '9', '+', '/' };

  public BASE64Encoder() {

  }

  public static String encode(byte[] a) {
      int totalBits = a.length * 8;
      int nn = totalBits % 6;
      int curPos = 0;// process bits
      StringBuffer toReturn = new StringBuffer();
      while (curPos < totalBits) {
          int bytePos = curPos / 8;
          switch (curPos % 8) {
          case 0:
              toReturn.append(codec_table[(a[bytePos] & 0xfc) >> 2]);
              break;
          case 2:

              toReturn.append(codec_table[(a[bytePos] & 0x3f)]);
              break;
          case 4:
              if (bytePos == a.length - 1) {
                  toReturn
                          .append(codec_table[((a[bytePos] & 0x0f) << 2) & 0x3f]);
              } else {
                  int pos = (((a[bytePos] & 0x0f) << 2) | ((a[bytePos + 1] & 0xc0) >> 6)) & 0x3f;
                  toReturn.append(codec_table[pos]);
              }
              break;
          case 6:
              if (bytePos == a.length - 1) {
                  toReturn
                          .append(codec_table[((a[bytePos] & 0x03) << 4) & 0x3f]);
              } else {
                  int pos = (((a[bytePos] & 0x03) << 4) | ((a[bytePos + 1] & 0xf0) >> 4)) & 0x3f;
                  toReturn.append(codec_table[pos]);
              }
              break;
          default:
              //never hanppen
              break;
          }
          curPos+=6;
      }
      if(nn==2)
      {
          toReturn.append("==");
      }
      else if(nn==4)
      {
          toReturn.append("=");
      }
      return toReturn.toString();

  }
}
